The purpose of the proposed research is to reveal principles of nervous function in the control of basic motivated behavior patterns. We are finding that hypothalamic reward and punishment mechanisms serve a homeostatic function by translating physiological imbalances into corrective behavioral action. Electrical stimulation of certain brain regions can be rewarding as evidenced by self-stimulation behavior, or it can cause aversion shown by responses to escape from stimulation. Our research is demonstrating that lateral hypothalamic self-stimulation and stimulation-escape are controlled by the same oral and postingestional factors which control feeding. The factors which augment food intake increase the reward of self-stimulation and decrease escape; conversely, satiety factors cause a shift from reward to aversion. It therefore appears that hypothalamic reward is involved in rewarding eating when the animal is hungry, and hypothalamic aversion is involved in punishing eating when the animal is satiated. The proposed research program has grown out of this work. We plan a series of integrated studies of (1) the role of the ventral noradrenergic bundle in the inhibition of feeding and self-stimulation; (2) hypothalamic unit recording; (3) a study of reward and aversion as related to copulation and (4) as related to addition.